Wireless communication systems of various kinds are known in the art. Many such systems use wireless communication units to sense signals from neighbor cells to determine the strength of such signals. This measurement helps to ensure efficient handoffs for wireless communication units that move from one cell to another.
The neighbor cell measurement done by many known wireless communication systems occurs when the wireless communication unit has assurance no data will be sent to it for a sufficient length of time, which allows the transceiver to receive the signals from one or more neighboring cells allowing for a measurement of the strength of these signals. For example, a neighbor cell measurement opportunity exists when a system using only one transmission or communication channel makes a reservation of sufficient length on the communication channel to another wireless communication unit in the cell. Because the wireless communication unit monitors only a single communication channel and reservations of sufficient length occur often, neighbor cell measurement opportunities are quite frequent.
Certain known wireless communication systems utilize multiple communication channels. An example of such a system is the so-called Wideband iDEN® (WiDEN) technology. Some of these known systems perform neighbor cell measurements only when certain conditions occur. For example, neighbor cell measurement opportunities may only occur when all communication channels have sufficiently long reservations at the same time. To ensure proper handoffs, a wireless communication unit having the certain conditions necessary to make neighbor cell measurements will typically make the measurement according to a predetermined schedule such as once every 180 milliseconds on average. If the certain conditions do not occur, the wireless communication unit will delay making the scheduled neighbor cell measurements. Because neighbor cell measurements are necessary to ensure proper handoffs, however, the wireless communication unit will stop all communication to forcibly make neighbor cell measurements once a certain number of neighbor cell measurements are delayed. During this mode of operation typically called a forced neighbor cell mode, the wireless communication unit stops sending and receiving data for the amount of time necessary to make all of the delayed neighbor cell measurements thereby ensuring proper handoffs between cells. Such delays in data transmission during a forced neighbor cell mode may significantly harm the data throughput of the wireless communication unit.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.